The positions of the
panels provided a baseline for the truss design. The design was
then optimized to provide maximum rigidity with minimum mass.
Optimization variables included; position of the node-balls and
diameter and wall thickness of the truss elements.

MSC/NASTRAN optimization
module was used to optimize for maximum rigidity, minimum mass
subject to accuracy requirement of < 40 microns RMS distortion
of reflector nodes due to gravity sag.